Force HALs to explicitly enable legacy method for clearing buffer caches

Some HAL implementations can't support setLayerBuffer multiple times to
clear the per-layer buffer caches. Therefore, default this behavior to
disabled, and allow HALs to explcitily enable this behavior to obtain
the necessary memory savings.

Test: play videos with both true and false on both HIDL and AIDL
Bug: 285561686
Change-Id: I928cef25e35cfc5337db4ceb8581bf5926b4fbe3
diff --git a/private/property_contexts b/private/property_contexts
index 19bd51a..64e738f 100644
--- a/private/property_contexts
+++ b/private/property_contexts
@@ -1323,6 +1323,7 @@
 ro.surface_flinger.display_update_imminent_timeout_ms     u:object_r:surfaceflinger_prop:s0 exact int
 ro.surface_flinger.uclamp.min                             u:object_r:surfaceflinger_prop:s0 exact int
 ro.surface_flinger.ignore_hdr_camera_layers               u:object_r:surfaceflinger_prop:s0 exact bool
+ro.surface_flinger.clear_slots_with_set_layer_buffer      u:object_r:surfaceflinger_prop:s0 exact bool
 
 ro.sf.disable_triple_buffer u:object_r:surfaceflinger_prop:s0 exact bool
 ro.sf.lcd_density           u:object_r:surfaceflinger_prop:s0 exact int